Along with rodeo, more rodeo and a little rodeo on the side, Wyoming summers also are known for their volatile, sometimes violent thunderstorms that produce lightning, hail and tornadoes.
Those on state’s eastern plains got an in-your-face reminder Thursday afternoon when a supercell thunderstorm hammered swaths of Converse, Goshen, Laramie, Niobrara and Platte counties.
"Trained weather spotters" located a severe thunderstorm 25 mph east of Wheatland at the same time the watch was issued, moving across southeast Wyoming at 25 mph, the agency reports.
"We're getting reports of hail up to softball-size and multiple reports of a tornado with the supercell," Gerry Claycomb, lead forecaster for NWS Cheyenne, told Cowboy State Daily. "It's moving eastward toward the Nebraska panhandle pretty quickly.”
It was just the start of a turbulent afternoon for easter Wyoming, said Cowboy State Daily meteorologist Don Day.
"There's going to be more of these thunderstorms through the rest of the afternoon and evening, mainly in the most far eastern counties and into the southeast," he said.
Photos and videos of the supercell storm on social media show the ground blanketed with hail in some areas and a tornado-like feature that seems to be on the ground in another.
Supercells
Supercells, or rotating thunderstorms, are the least common but most severe type of thunderstorm. Although they are usually isolated and only last a few hours, they can quickly cover a wide area and cause extensive destruction.
Wyoming is a perfect canvas to generate them in the summertime.
"Thunderstorms are small-scale," Day said. "They don't have the big, wide coverage that fronts and storms do. You tend to have these storms on a localized basis. It was really unstable today in the eastern side of Wyoming, and it will be again tomorrow."
Day said a combination of good moisture, daytime heating and the end of the cold front that descended on northwest Wyoming earlier this week contributed to the Thursday afternoon thunderstorm. Day said supercells are fast and furious, making them a huge threat for a brief moment.
"They move along at a pretty good clip, 25-35 mph," he said. "But supercells evolve and change. They'll intensify and very rapidly move through an area, then fall apart just as quickly as they form. But you get more forming throughout the heat of the afternoon, and once the atmosphere settles down in the late afternoon, you'll see them dissipate."
Supercells are more common during the summer and can sometimes happen fairly frequently in Wyoming. Day was surprised it's taken this long for a supercell to form this season.
"We honestly have not had a lot of severe weather so far this season," he said. "This is probably one of the most active afternoons of severe weather we've had so far. This time last year, we had a lot more than what we've seen so far this year."
Staying Safe
Day anticipated that there will be more severe weather in Wyoming on Friday. Northcentral Wyoming should expect isolated thunderstorms and the possibility of a supercell during the afternoon.
"Severe weather has been more concentrated in the east and the southeast today," he said. "It'll get into and cover a larger area of central and northern Wyoming tomorrow."
Claycomb said the best way to stay safe during a supercell is to avoid it altogether. If anyone driving on a Wyoming highway encounters a supercell, attempt to get away from the path of the storm.
"You don't want to go forward," he said. "You want to stop and safely turn around and move away from the storm or in the opposite direction if you can. But you'll want to stay with your vehicle. If there's a tornado with it, find a ditch and get down in the ditch. It won't protect you from the hail, but it might give you some safety from the tornado."
Day said drier air and less moisture will reduce the risk of supercells over the weekend.
"The risk of severe weather is high on Friday, but drops over the weekend," he said. "There may still be thunderstorms, but not nearly as many as the air gets drier.”
Contact Andrew Rossi at arossi@cowboystatedaily.com
What appears to be a tornado toucheds down Thursday in eastern Wyoming. A supercell thunderstorm brought volatile weather. (National Weather Service, Cheyenne) 
Hail blankets the ground and vehicles like a snowstorm Thursday in eastern Wyoming. A supercell thunderstorm brought volatile weather, including hail, which was reported to be softball-sized in some areas. (National Weather Service, Cheyenne) 
Hail blankets the ground and vehicles like a snowstorm Thursday in eastern Wyoming. A supercell thunderstorm brought volatile weather, including hail, which was reported to be softball-sized in some areas. (National Weather Service, Cheyenne)
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
